Q 35 - Immutable strings

[HARSHITH-MV]

Why are Strings immutable in Java?

[AmjustGettingStarted]

🧵 Strings in Java are immutable once created, they cannot be changed. This may seem limiting at first, but it’s a clever design choice with several powerful benefits:

🚀 Benefits of String Immutability

• Security: Strings often store sensitive data like file paths, database URLs, or credentials. If they were mutable, someone could change them after validation. That’s a security risk.
• Thread Safety: Immutability makes Strings automatically thread-safe. Multiple threads can work with the same String object without synchronization concerns.
• Caching & Interning: Java uses a String pool for memory efficiency. Immutable Strings can be safely shared two identical Strings point to the same object, saving memory.
• Hashing Performance: Strings are frequently used as keys in hash-based collections like HashMap. Immutable objects guarantee the hash won’t change, ensuring consistent lookup behavior.
• Class Design Simplicity: Immutable classes are easier to design, test, and maintain. Strings benefit from this reduced complexity.

🔧 How It Works

When you modify a String, you're not changing it you’re creating a new one:

String name = "Java";
name = name.concat(" Rocks!");

This doesn't change "Java" it creates a new String "Java Rocks!".